Opera, said the Italian composer Rossini, could be truly wonderful if only there were no singers. What the creator of such opera classics as The Barber of Seville and Cenerentola would have made of the latest reality television show – Popstar to Operastar – is anyone's guess. But it has led to a chorus of disapproval in the rarefied world of divas and fat ladies and gentlemen.

The soprano Rebecca Evans, who appears regularly with Welsh National Opera and the Royal Opera, has led the criticism against the reality show in which pop artists such as Alex James of Blur and Bernie Nolan of the Nolan Sisters are taught to know their arias from their entr'actes by established singers such as Katherine Jenkins and Rolando Villazon. The choice of Jenkins has been criticised because she is not herself an opera singer, but a performer of stand-alone arias. The pop singer Meat Loaf also appears on the show as a judge.

"I think it's exploiting the world of opera," Evans said of the ITV show hosted by Myleene Klass. "They will be calling more people opera singers when they are not opera singers – it's television gone mad. Being an opera star is working in an opera house where you spend six weeks in a rehearsal room planning for the production. Opera singers are like athletes – you have to have stamina. It takes years of hard graft and dedication to become an opera singer. The series will give the wrong impression."

Sarah Connolly, in rehearsals for Ariadne at the Metropolitan Opera, New York, said the programme had provoked a fierce debate among fans of opera on social network websites such Facebook. "Half think it's a bit of fun and half think it's terrible," said Connolly, a mezzo-soprano who was made a CBE in the New Year's honours list. "It should be taken as a bit of fun. I don't think Alex James is going to go on to be an opera star. But they do need to point out that opera isn't just about singing. That's just the start. You have to study the psychology of the character and the intention of the composer. We attempt the big questions in life and try to interpret the score on a deeper level. It's not just about getting the notes in the right order."

The theatre and opera director Sir Peter Hall, who was artistic director of the Glyndebourne Opera Festival in the 1980s, argued that widening the audience for opera could only be a good thing. "I'm more worried about young singers," he said. "You damage your voice by not using it properly. There are many examples of young singers who sing too difficult notes too early and lose what they have."

The tenor Russell Watson also supported the show. "I think it's a good thing that 'opera' is being presented in a prime-time slot," he said. "I've been a huge supporter of popularising this genre. Long may it continue."

Katherine Jenkins also denied the show would "dumb down" the form. "It will show people how difficult it is to sing opera," she said. "Viewers will be able to see the training sessions and understand what happens."